In the installation of dry-wall one of the major time-consuming tasks is the attachment of the outside corner bead. Performed manually, this task requires holding the corner bead in place and nailing from two directions on either side of the bead. Under these circumstances, the bead is often misaligned with the corner resulting in the operation having to be repeated, if an acceptable corner is to result.
For this reason, a number of devices have been designed to simplify the attachment of corner bead. For example, U.S. Pat. No. 5,524,087 describes a handled fastener tool which includes first and second fastener guns supported by a handle, at a predetermined angle in relation to each other and the intersecting walls. The first and second fastener guns drive respective fasteners into the corner bead and are triggered by a single trigger mechanism that actuates both guns simultaneously.
Similarly, U.S. Pat. No. 5,667,126 describes a tool comprising a pair of fastener ejecting guns secured to a handle in parallel relationship and in a predetermined angular relationship with respect to one another and with the corner bead being attached. The tool includes a trigger assembly for simultaneously actuating the actuating levers of both guns.
While these patents describe useful tools for installing drywall bead, they fail to address a major problem often encountered with such installations, namely, that the corner to which the bead is being attached is not square due to irregularities in the underlying studding or simply shoddy carpentry. Even under the best of circumstances, individual outside corners within a given structure will vary in angular dimension even though they may be relatively uniform along their respective individual lengths. Thus devices as described in the prior art which place the pair of guns at a predetermined or fixed angle can provide an inferior installation by allowing the bead stand removed from the wall surface along its length as the shape of the corner changes therealong or from individual corner to individual corner.
The device of the present invention is, on the other hand, designed with a hinged structure that allows a pair of simultaneously activatable guns to rotate with respect to one another so to fit the shape of the outside corner to which the corner bead is being attached. The flexibility of the hinged design described herein allows use of the tool on corners that can vary quite significantly in their relative angular configuration.